The charging and exhausting of alternate sides of the piston in an air cylinder is accomplished by an air control assembly connected to the cylinder ports. Some of the disadvantages of cylinder-mounted control assemblies are that they must be factory installed because they are specially adapted for mounting only on a particular air cylinder, or when adapted to be mounted in the aftermarket require modification to the cylinders in order to attach the control assemblies, for example, by the drilling and tapping of bolt holes. In some instances the control assemblies cannot be mounted on air cylinders having a standard rear clevis mount centrally of the cylinder because they occupy that space. Many control assemblies when mounted on a cylinder extend over the edges or outward extremities and invade the cylinder mounting surfaces. Many control assemblies are limited and cannot accommodate an air cylinder having a piston rod travel below a certain minimum distance such as two inches.